The Purple Swamphen is a large rail. It is mainly dusky black above, with a broad dark blue collar, and dark blue to purple below. As the Purple Swamphen walks, it flicks its tail up and down, revealing its white undertail. The bill is red and robust, and the legs and feet orange-red. For such a bulky bird, the Swamphen is an accomplished flier and will readily take to the air to escape danger.